Supervisory system



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SUPERVISORY SYSTEM Filed Dec. 11, 1929 3 Sheets-Sheet 3 Invent or:

m His Att vne Patented Feb. 6, 1934 SUPERVISORY SYSTEM Clyde E. Stewart, Drexel Hill, Pa., assignor to General Electric Company, a corporation of New York Application December 11, 1929 Serial No. 4 13,354 1 Claims. (01. 177-353 My invention relates to remote control systems, and more particularly to the type of re mote control system in which selector equipment located in the control, or dispatchers, station 5 andsimilar equipment located in a remote station are operated synchronously over line conductors extending between the stations. tem of this nature has been disclosed in my copending application, Serial No. 260,168 filed 1) March 8, 1928 entitled Supervisory control systems, corresponding to Br'tish Patent 307,469,

which is assigned to the same assignee as my present application and of which the present ap plication is a continuation in part.

In systems of this type a number of line conductors are employed over certain of-which the synchronous selector equipment in the different stations is operated and over others of which remote control and indication functions are ef- 2o fected.

Among the objects of the invention to be disclosed by the present applicationis to provide means for preventing erroneous control and in- I dication operations to be efiected due to faults in the line conductors.

Another object of the invention is to provide means whereby suitable alarm and indication operations may-.be produced in response to a fault upon any of the line conductors such as an open circuit inany of the'line conductors or a short circuit between any of the line conductors.

A further purpose of the invention is to provide means whereby signal or other means in both stations may be operated when certain faults in the line conductors occur.

A further purpose of the invention is to provide means whereby when the supervisory system is utilized to control the functioning of automatic control equipment in a remote station as, for

40 example, to render said equipment effective or ineffective to bring about desired operations, said equipment may be automatically rendered ,effective in response to a fault in a line conductor, or other condition corresponding to disability of the supervisory equipment.

Still another object of the invention is to provide means whereby in case the system is set into operation in response to operation of a remote apparatus unit and for some reason, as for example failure of interlocks on the operated units to properly engage, continues in operation the selectors may be synchronized in the normal position, together with means whereby an alarm may be operated in the dispatchers station each time that the selectors engage the normal A SYS- contacts. A further purpose is'to provide means whereby the dispatcher, without leaving his station, may determine the particular apparatus unit in response to operation of which-the above failure occurred. a, p

The novel features which I believe to be char-' acteristic of my invention are set forth with particularity in the appended claims. My invention itself, however, both as to its organization and method of operation, together with further objects and advantages thereof may best be understood by reference to the following description taken in connection with the accompanying drawings inwhich Fig. 1 represents my invention as employed in a remote supervisory con-' trol system, and Figs. 2 and 3 represent my invention as applied to a system similar to that shown in Fig. 1, but which differs therefrom in that it is employed for indication only, and in that it is'of greater capacity.

Referring to Fig. l of the drawings I have shown a supervisory control system comprising a selector A located in the dispatcher's station and a corresponding selector A located in the remote station. Also .located in the dispatchers station are a plurality of control and indication panels, of which. only one is shown in the drawings, on each of which are mounted indicating lamps g, r, w and b, a control key 4 and a selector key 3. Each of these panels corresponds to an apparatus unit such as the switch 1' at the remote station which is to be controlled and supervised through the supervisory system. Extending between the stations are a pair of line conductors L3 and L4 over which impulses are communicated between the stations for the purpose of synchronously operating the selectors A and A' through their various positions thereby selectively to associate each of the control panels 1 with its corresponding apparatus unit. Conductor L-1 extending between the stations is connected between the wipers of the banks 0 and c' of the switches A and A and serves the purpose of transmitting impulses from the dispatchers station to the remote station for the purpose of controlling apparatus units. Similarly conductor L-2 connects wipers of the banks 1. and i of the switches A and A and serves the purpose of transmitting impulses from the remote stations to the dispatchers station to indicate the position of the remote apparatus units.

The system will best be understood by reference to its operation. Assume that the operator desires to check the position of each of the remote switches 1'. He operates the start key 6 to its circuit closing position thereby completing a circuit which extends from the negative side of the battery 10 through the left-hand contacts of relay 42, upper contacts or start key 6, normal contact and wiper of the bank i of switch A contacts 43 oi. the emergency reset key 5, conductor L-2, wiper and normal contact 01 the bank 1" of the switch A, relay 44 to a neutral point on the battery 13 at the remote station. It will be observed that the neutral points on the batteries 10 and 13 are directly connected through the conductor L-4 and the contacts of relay 50 at the remote station.

Relay 44 then closes its contacts and completes a synchronizing circuit including the conductor L3. This circuit extends from the positive side of the battery 13 through conductor 45, contacts of relay 44, normal contact and wiper of the bank s of the switch A, synchronizing polarized relay p, conductor L3, synchronizing polarized relay p at the dispatchers station, wiper and normal contact of the bank s of the switch A, upper contacts of key 5, right-hand contacts of relay 46, left-hand contacts of relay 4'7 to the negative side of the battery 10. Relays p and 1) will then be operated to the position opposite to that shown in the drawings, each relay thereby completing a circuit for the motor magnet of the corresponding selector switch. In the dispatchers station this circuit extends from positive potential at the normal contact of the bank n through motor magnet 48 and its interrupter contacts to negative potential at the upper armature of relay p. The corresponding circuit at the remote station extends from positive potential at the normal contact of the bank n through the wiper, motor magnet 49 and its interrupter contacts to negative potential at the upper armature of relay p. Both magnets are energized in these circuits and in actuating their armatures interrupt their energization circuit and thereby operate the selector switches to the next position.

It will be noticed that the successive contacts of the bank s of switch A are connected alternately to the positive and negative side on the battery 10 through keys 3 and conductors 37 and 88. In the same way alternate contacts in the bank s of the switch A are connected to opposite sides on the battery 13 through conductors 14 and 15. Thus when the wipers of the banks s and s of the switches A and A engage their first oil-normal contacts the polarized relays p and p are again energized with current of opposite polarity from that which caused the previous actuation. These relays then return to the position shown in the drawings. It will be noticed also that alternate contacts of the banks n and n of switches A and A are likewise connected to opposite sides of the corresponding batteries. Accordingly when the relays p and p return to the position shown in the drawings the circiu'ts of the motor magnets are again energized. In operating the motor magnets interrupt their own circuits and step the wiper to the second off-normal position where the motor magnets become again deenergized by virtue of the fact that their circuits extend from the wiper of the bank n to a point of like polarity at the upper armature of the relays p. The current in the synchronizing relays, however, is again reversed by the wipers of the banks s and s causing a successive operation of the armatures and of the motor magnets of the respective selector switches. In this way it will be apparent that the switches operate synchronously throughout a complete revolution and return to the normal position where the circuit of the relays p and p are interrupted at the contacts of relay 44 which is now deenergized. Thus upon operation of the start key the selectors operate through a complete revolution and return to the normal position.

When the switches A and A engage their first off-normal contacts a circuit is completed which extends from the positive side of the battery 13 at the remote station through conductor 45, contacts 35 which cooperate with an interlock 35 on .the switch 1', first of! normal contact and wiper oi the bank 2" of switch A, conductor L-2, contacts 43 on the reset key 5, wiper and first oilnormal contact of the bank i of the switch A, and polarized indication relay 26 to the neutral point on the battery. Had the switch 1' been in its closed position this circuit would have extended from the negative side of the battery 13 through the contacts 34 which cooperate with the interlock 35 on the switch 1 and, accordingly, the current in the circuit traced would have been of reversed polarity. Thus the armature of relay 26 assumes either oi! its two positions depending upon the position of the switch 1' and thereby, through obvious circuits controls the lamps g and r to indicate the position of the remote switch. A similar circuit (not shown) is completed through each of the different contacts of the banks 2' and i of the switches A and A to indicate the position of the remaining apparatus units (not shown).

Let us assume that the operator desires to change the position of the switch 1. He will first operate the key 4 to the position opposite that shown in the drawings thereby completing a circuit from the negative side of source 39 at the upper contact of the key 4 through the lamp w to the positive side of source 39 at the armature of relay 26. The lamp w informs him that the position of the key no longer corresponds to that of the corresponding remote apparatus unit. He will then operate the corresponding key 3 to its circuit interrupting position, thereby deenergizing the circuit of synchronizing relays p and p when wipers of the banks's and s engage the corresponding contacts. He will then operate the start key 6. When the switches A and A occupy the position corresponding to the key 3 which is operated the relay 53 will through means later to be described become energized, and through its left-hand contacts complete a. circuit from the positive side of the battery 10 through resistance 54, left-hand contact of relay 53, lamp b on panel 1, wiper of the bank t through the neutral point on the battery 10. The lighting of the lamp 2) informs the operator that the switches A and A are on contacts corresponding to the key 3 which has been operated. The operator will now press his control key 7 thereby completing a circuit which extends from the negative side of the battery 10 through conductor 88, lower contact of key 4, wiper of bank 0 of switch A, inner left-hand contacts of relay 53 which are now closed, contacts of the key 7, conductor L-l, armature of relay 55, wiper of bank 0 and control relay 26 to the intermediate point on the source of potential 13. The polarity of current in this circuit will be seen to be dependent upon the position of the key 4 and, accordingly, the polarized relay 26 will assume a position corresponding to the polarity of the current in its winding. The-closing coil 16 will thus be energized to operate the switch. When the switch operates to its closed position the polarity of current in the indication circuit previously traced will be changed thereby correspondingly operating relay 26 to extinguish lamp 9 and energize lamp 1' on the panel 1. The lamp w is now extinguished since both terminals of its circuit are connected to points of like polarity. If the operator desires to operate the switch to its original position, he will again change the position of the key 4 and press the control key.

When the control operations have been completed the operator will then press the key 3 to its circuit-closing position thereby causing the selectors to return to the normal position which is that shown in the drawings.

The operation of the equipment in response to an automatic operation of a supervised apparatus unit is as follows:a relay 30 is associated with each of the apparatus units. This relay is normally energized in a circuit extending from the intermediate point on the battery 13 through the right hand contacts of relay 30 to either the positive or negative side on the battery 13- depending upon the position of the interlock 35. When the switch 1 changes position, as due to some automatic operation, this circuit is momentarily opened and the polarity-of current in the winding of relay 30 is reversed as the interlock 35 is moved away from its contacts 35 and into engagement with its contacts 34. Relay 30 then operates its armature to the position opposite to that shown in the drawings thereby interrupting its normal circuit and completing a circuit through its left-hand contacts for the relay 36. The contacts of relay 36 are connected in parallel with the contacts of relay 44 which was previously operated in response to operation of the start key 6. Thus by energization of relay 36 the selectors will be started into operation and will complete a revolution. When the selector is on the position corresponding to the unit operated, the indicating circuit which was previously traced is completed to operate the corresponding relay 26 at the dispatchers station thereby to change the lamps. A further circuit at the remote station will be completed which extends from the intermediate point on the battery 13 through wiper of the bank t and the contact corresponding to the operated unit, relay 30, and interlock to one side of the battery 13 depending upon the position of the switch. Relay 30 will then again be restored to its normal bi energized condition and will complete a locking circuit for itself by means of its right-hand contacts.

Since the position of the armature of relay 26 no longer corresponds to the position of the key 4 the white light will be lighted informing the operator as to which of the remote switches operated.

When the switch A is operated from its normal position in response to the above described automatic operation, a signal bell 8 at the dispatchers station is operated. This bell as will later be indicated is also operated in response to faults on the line wires and loss of battery potential. The operator on' hearing the bell will examine the lamps W to determine what remote unit operated. If no lamp W is operated he will conclude that there is line wire trouble or a loss of operating potential. As will be explained hereinafter the fact that the lamp W is not operated may also indicate that the selectors are not in synchronism. This bell 8 is operated in response to operation of relay 61 which is normally connected in a circuit which extends from the intermediate point on the battery 10 through T; wiper and normal contact of the bank t of switch switches the right-hand contacts thereof are in A, contacts of relay 62, winding 01' relay 61, lower contacts or key 7, line L--1, contacts of relay 55, wiper of bank 0' on its normal contact, contacts of relay 65, winding of relay 61' to the positive side of the battery 13. Thus when either of the switches A or A leaves its normal contact this circuit is interrupted causing deener-' gization of the relay 61, at the dispatcher's station and 61' at the remote station. Relay 61' may similarly be used to control alarm or other automatic apparatus as shown in Fig. 1 at the remote station. Upon deenergization of relay 61, at the dispatchers station relay 42 becomes deenergized and operates its armature to the position opposite that shown in the drawings. Whenthe right-hand armature of relay 42 moves from the position shown to the opposite position or vice versa it momentarily interrupts an obvious circuit for relay 63. Relay- 63 then operates its armature to the position opposite that shown in the drawings thereby completing an obvious circuit extending through the winding and interrupter contacts of the hell 8 causing the bell to operate. In case the contacts of the key 9 are open the bell will operate continuously. In case the operator has previously closed these contacts, upon operation of relay 63 and the first opera tion of the bell 8, as of a' gong, the relay 64 will respond, it being connected in series with the winding of bell 8. Upon closing its contacts relayv 64 again completes an energizing circuit for the re1ay 63 through its contacts and the middle contacts of relay 63. Relay 63 is then again energized and in closing its left-hand contacts completes its own holding circuit. When contact 66 on the relay 42 changed position the current in relay '70 reverses in polarity after being momentarily interrupted. This relay then becomes deenergized and-through its left-hand contacts'operates a pilot lamp 67. The purpose of the lamp- 67 is to indicate that the supervisory system has operated in response to the automatic operation. This indication is useful where a large number of systems are employed in the same station to indicate which system operated. The operator may extinguish the light by pressing the pilot light key 68, thereby completing an energizing circuit for the relay 70 whereby upon energization of its right hand contacts it completes its own energizing circuit.

Relay 42 also deenergizes lamp G therebyinforming the operator that the selectors 'are not in the normal positions.

When the selectors are returned to their normal position, as has been previously stated, the circuit of the synchronizing relays p and p is interrupted at the contacts of relay 44. It may occur, however, that due to surges upon the indication or synchronizing conductors as the selectors reach the normal contacts, relay 44 or the 135 polarized relays p and p may be actuated thereby causing the selectors to be operated to a succes- .sive position. To prevent this contingency relay 46 is inserted. This relay is connected between the point of positive or negative polarity depending upon the position of relay p and the intermediate point' on the battery 10. This relay is of the slug type and is slow to energize such that during rapidly reversing polaritythrough its winding as during the stepping operation of the 1 their open circuit position. Hence the starting circuit through the polarized relays which was previously traced is interrupted. After an interval following stopping of the selectors relay 46 159 becomes energized and upon actuating its lefthand contacts deenergizes relay 47. Relay 47 is of the slug type and is slow to deenergize. Thus after a further interval its left-hand contacts close and thereby complete the circuit of the polarized relays p and p. In the meantime the surge on the line conductors will have dissipated itself and the selectors will remain upon the normal contact.

It will thus be apparent that whenever the switches stop in any position an interval of time elapses before the right-hand armature of relay 47 operates to its open circuit position. This effect is utilized in a manner presently to be described.

If during the operation of the selectors they assume non-corresponding contacts and the polarized relays thereby become deenergized, it is desirable that the control conductor should be interrupted thereby to prevent the occurrence of an erroneous remote control operation. For this purpose among others, the relays 69 and 53 are included. Relay 69 is connected between the lower armature of the relay p and a point between the polarized relay p and the wiper of the bank s. Thus, during the stepping operation the relay is deenergized. When the switches stop upon corresponding contacts relay 69 is energized through a circuit extending from the lower armature of relay p through the winding of relay 69, relays p and p to a point of polarity opposite to that of the lower armature of relay p as determined by the position of the wiper'of bank s of switch A. The current flowing in this circuit will be sufficient to operate relay 69 although it is not sufiicient to operate relays p and 1). When relay 69 operates it completes a. circuit which extends from an intermediate point on the battery 10 through the contacts of relay 69, right-hand contacts of relay 47 which are closed for an instant after the switch has stopped, and winding of relay 53 to the negative side of the battery. Operation of relay 53 causes the lamp b to be lighted to indicate the position of the switches A and A. By means of its inner left-hand contacts relay 53 completes the control circuit. By means of its inner right-hand contacts it completes a holding circuit for itself through the contacts of relay 69. By means of its outer right-hand contacts it interrupts a short circuit about the lower portion of resistance 78 thereby rendering relay 69 more sensitive to voltage variations. If now, due to a loss in synchronism the selector A is not upon 'a contact corresponding to the position of the relay p, relay 69 will be deenergized and will prevent energization of relay 53 which in turn maintains the control circuit open, the lamp b deenergized and a shortcircuit completed about a portion of resistance '78. Relay 53 cannot be energized until completion of a successive operation of the selectors after which the contacts of relays 69 and 47 are simultaneously closed thereby again completing the circuit of relay 53.

As has been previously explained, my present invention relates to safety devices used in connection with the system and more particularly to the manner in which the operation of the system is protected against faults in the line wire circuits and the manner of producing an alarm when a fault occurs in the line conductors. The means whereby this is effected will now be explained.

It will be seen that the circuit of relays 61 and 61 includes the line conductors L--1 and L-4. Upon occurrence of an open circuit in either of these conductors these relays will be deenergized. Relay 61 in operating will deenergize relay 42 thereby as previously described operating the signal'device 8 and at its left-hand contacts interrupting the starting circuit so that the equipment cannot be started into operation while this condition exists.

Relay 62 which has a relatively high resistance is connected in a circuit which extends from the negative side of the battery 10 through relay 62, wiper of bank 2' of switch A, contacts 43 of the reset key 5, conductor L2, wiper of the bank i of switch A and relay 44 to an intermediate point on the battery 13. ,The current in this circuit is sufficient to operate the relay 62 but is not sufficient to efiect the operation of the relay 44.

Thus, if the conductor L-2 becomes interrupted relay 62 will be deenergized and in opening its contacts will deenergize relays 61 and 61'.

Relay 65 at the remote station is connected in shunt with the contacts of the starting relays 36 and 44 and is hence normally energized in series with the line L3 and the relays p and 1). Its contacts are included in the circuit of line Ll and relays 61 and 61'. Thus, upon interruption of line L3 relay 65 becomes deenergized and, accordingly, deenergizes relays 61 and 61.

- Relay 61 will similarly be operated in response to short circuits between conductors L-1 and L-2. It will be seen that the normal energizing current for relay 61 in the dispatchers station is supplied from the positive half of battery 13 through relay 61' and conductor L-1. Thus, if conductor L1 is shorted to conductor L-2, a path is completed through the short circuit between L1 and L-2 and relay 44 at the remote station to the neutral point on the battery 13. A further circuit will extend from conductor Ll through the short circuit to conductor L2 and thence through relay 62 in the dispatchers station to the negative side of the battery in the dispatchers station. The resistance of these paths, as compared with the resistance of relay 61, is such that the current flowing in the winding of relay 61 will be very materially reduced and sumcient to cause operation of its contacts. If desired relay 44 may be sufficiently sensitive to operate in response to this short circuit in which case the selectors will step and deenergize relay 61.

If a short exists between line L--1 and line L3 a connection is established from the negative terminal of the battery 10, left-hand contact of relay 47, right-hand contact of relay 46, upper contacts of reset key 5, normal contact and wiper of bank S of switch A, winding of polarized relay p, line L3, the short-circuit between lines L-3 and Ll, lower contacts of key 7, winding of relay 61, contacts of relay 62, and the wiper of bank t on its normal contact. The current in this connection will sufficiently increase the current flowing in the winding of relay 1) .to operate the selector A from its normal contact thereby deenergizing relay 61.

If the line Ll becomes shorted to line L--4 a direct short circuit will exist across relay 61 causing its deenergization.

If line L2 becomes shorted to line L3 sumcient current will flow from line L3 to line L2 and thence through the wiper of the bank 2" of switch A and relay 44 to the intermediate point on the battery .13 to cause operation of reenergizes the relays 61 and 61'.

It lines L-2 and L-4 become shorted relay 61 will not be deenergized and hence the alarm bell will not be sounded but it will be seen that the operator cannot energize relay 44 by operating the start key. Accordingly he is unable to operate the equipment.

If line L3 and line L-4 are shorted, it will be seen thatline- L-3 will be connected directly to the intermediate point on the battery 10 and, according y, selector A will start into operation and will continue to operate until power is removed from the system or the fault condition is corrected. Relays 61 and 61' will of course be deen- Y ergized and sound the alarm.

In case the battery potential at the remote station becomes reduced to a predetermined value relay 50 at the remote station operates and thereby interrupts the circuit oi the line conductor L-4 which in turn deenergizes relay 61 and 61' and causes the alarm bell to be operated.

It will thus be seen that when an open circuit or a short circuit. condition exists in the line conductors, or the battery potential at the remote station becomes reduced to a predetermined value, the alarm bell will be sounded in the dispatchers station with the exception of the case of a short circuit between line conductors L--2 and L-4 where no indication is produced but in which the dispatcher is unable to start the equipment.

The relay 61' connected as shown in the drawings is important in a number of ways which will presently be explained.

Its outer left-hand armature may be utilized to control an alarm arrangement 8' which may, for example, include a bell, controlled as shown at 66, '70, 67 and 68 or 63, 64, 9 and 8 at the dispatchers station, or lamp, or drop as desired.

Its inner left-hand contacts may be utilized to control a time-delay relay 61" thereby to cause its operation after a predetermined interval subsequent to each deenergization of relay 61 as due to a line fault or the stepping of the switch A from the normal position. This relay 61" is of importance, particularly, in connection with the remote supervision of automatic substations where remote control is superposed upon the automatic control of the station.

To illustrate, let us suppose that the contacts of relay 26" are connected in series with the master control circuit, or master relay, of the control system of certain equipment as for example an oil switch, or motor generator set, at the substation. When these contacts are closed this circuit is subject to control through automatic equipment indicated at 87 in the drawings whereby the equipment may be automatically controlled, opened or closed if it be a switch, or started or stopped if it be a generator in accordance with predetermined conditions at the substation. When these contacts are open the master circuit is interrupted and the equipment may not then be started by the automatic devices Relay 26" is of course normally controlled through the supervisory equipment in the same manner as relay 26'.

Upon disability of the supervisory equipment it is desirable automatically to close the contacts of relay 26" thereby to permit automatic control of the equipment above mentioned. This is accomplished as illustrated in the drawings by supplying positive potential from battery 13 through the contacts of relay 84 to the left-hand terminal of relay 26". Relays 84 and 85 are connected in multiple in an obvious circuit to respond to operation of relay 61",

Thus, upon occurrence of a line wire fault or other occurrence, causing the switch A to leave its normal contact for a predetermined interval relay 61" and hence relays 84 and 85 respond thereby actuating all relays such as 26" in the station to the position to permit control of the corresponding devices through the automatic devices provided. It will be understood, however, that the time-delay oi! relay 61" is sumcient to permit normal control operations through the equipment without operating relays 84, 85 and 26". e

A further important function of relay 61' ,resides in connection with faulty operation of the interlock 35' on the supervised devices 1'. Thus, for example, let us suppose that the switch 1' shown in the drawings operates automatically to its upper position thereby deenergizing relay 30 and causing actuation of the starting relay 36 and hence starting the supervisory system into operation. Normally when the switch A reaches itsfirst off-normal contact the position indication is transmitted to the dispatchers station and relay 30 is again energized through a restoring circuit including the wiper and first qfi-normal contact of bank t, relay 30 and interlock 35 in engagement with contacts 34.

Let us suppose, however, that interlock 35' makes faulty connection with contacts 34 and this restoring circuit is not completed. Relay 36 will be energized through the right-hand contactsof relay 61', each'time the switches A and A return to normal position, thus closing the circuit of line L--3 through the selectors A and A in the normal position and causing the switches A and A to restarteach time they return to normal. Thus each time the switches A and A return to normal the alarms 8 and 8' ring advising the dispatcher and substation operator of this condition. This is repeated until the equipment is stopped by the dispatcher or the fault is corrected.

If during this operation, for any reason, the switches A and A lose synchronism, the equipment will stop. The dispatcher, however, can resynchronize the switches A and A by pressing and holding his emergency reset button 5 through its lower contacts, thereby connecting line L3 to the midpoint on batteries 10 and 13, and opening at its upper contacts the cir- .cuit of L-3 in the'normal position, thus caus- It will be noticed that a meter 86 is included in circuit with line 1. 2 at the dispatcher's station. The purpose of this is to provide means whereby the dispatcher may determine, without leaving the station, the exact apparatus unit upon which the fault occurred. This maybe done by first synchronizing the selectors and then controlling the selector'switches 3 to cause the keys to stop upon each successive contact and observing the reading of the meter. An abnornially low reading of the meter is indicative of '150 the switch which is faulty. The dispatcher is then in position to give definite orders for the repair of a specific contact at the remote station.

When the selectors operate due to a fault in the line conductors faulty operation of relays 26, 26 is prevented by relay 53 at the dispatchers station and relay 55 at the remote station.- Relay 53, being deenergized, opens the control conductor. Relay 55 is slow acting and is connected between the armature of relay 1: and the intermediate point of battery 13. Its contacts are connected in the control conductor. It opcrates in a manner similar to relay 48 to maintain the control conductor open until the selectors stop.

When the operator hears the alarm he may correct the fault and then return the selectors to the normal position by operating the emergency reset key 5. By means of its lower contacts this key connects line L-3 directly to the intermediate point on battery 10 which in turn causes the selectors to return to the normal position. By its upper contacts the circuit of the relay p is opened when the switch A reaches the normal contact. The middle contacts similarly open the starting circuit including relay 44.

In Figs. 2 and 3 I have shown my invention as applied to a system employing synchronous selectors solely for indicating the position of remote apparatus units. Its operation is essentially the same as that described in connection with Fig. 1 withthe exception that both of the line conductors L1 and L2 are connected in the same manner to indicate the position of remote apparatus units. Thus the position of two apparatus units is indicated in each position of the selectors. The capacity of the system is increased by employing 2 selectors A and B in the dispatchers station and corresponding selectors A and B in the remote station together with a transfer selector T in the dispatchers station and a similar transfer selector T in the remote station. The selectors T and T operate to transfer the line conductors from the selectors A and A to the selectors B and B after the selectors A and A have been operated over their bank of contacts. The operation of the equipment will now be described.

The starting relays 36 and 44 having contacts connected in parallel are employed in the same manner as is done in connection with Fig. 1, the relay 36 being connected to operate in response to automatic operation of any remote unit and the relay 44 being connected to operate in response to operation of the start key 6. When either of these relays closes its contacts the synchronizing circuit through conductor L-3 is completed and the selectors A and A operate over their complete bank of contacts. It will be noticed that there are no means provided on the panels 1 and 2 etc. in the dispatchers station for stopping the selectors upon predetermined contacts.

When after having been set into operation the selectors A and A have reached their last contacts a circuit is completed in the dispatchers station extending from the neutral point on the battery to the wiper and last contact of the bank t of switch A, wiper and normal contact of the bank t of switch B, wiper and normal contact of bank t--5 of transfer switch T, and motor magnet of the transfer switch T to the positive side of the battery 10. A circuit through corresponding elements at the remote station will similarly be completed, thereby energizing motor magnets '71 and 71' of the transfer selector causing these selectors to operate to their first of! normal contact. In this position conductor L-3 and the synchronizing relays p and p are connected to the wipers of the banks 3 of the switches B and B. The indicating conductor L1 is now connected between the wipers of the banks i and i of switches B and B respectively. Similarly the indication conductor L-2 is connected between the wiper of the bank i" and the wiper of the bank i of the switch B and B respectively. The circuit of the motor magnets 48 and 49 of switches A and B are interrupted at the normal contacts of the bank t-4 of the switches T and T respectively, and the circuits of the motor magnets 72 and 73 of switches B and B are connected through the banks t4 of the switches T and T to the armatures of the polarized relays p and 1) respectively. Thus the selectors B and B are now connected to the line conductors in the same manner in which the selectors A and A were previously connected and will operate over their complete banks of contacts.

When the switches B and B reach their last contacts a circuit is completed at the dispatchers station which extends from the neutral point on the battery through wiper and last contact of the bank t of switch A, wiper and last contact of bank t of switch B, second contact and wiper of the bank t5 of the switch T, motor magnet 71 of the switch T to the positive side of the battery. A circuit through corresponding elements at the remote station is also similarly completed, thereby again energizing the motor magnets 71 and '71 of the switches T and T. Thus the switches T and T will now be operated to their third contacts. A circuit will then be completed at the dispatchers station which extends from the negative side of the battery 10 through wiper and third contact of the bank t3 of the switch T, last contact and wiper of the bank 1: of switch B, motor magnet '72, third contact and wiper of the bank t-4 of the switch T, armature of the relay p to the positive side of the source of potential. A circuit through corresponding elements at the remote station will likewise be completed thereby causing energization of the motor magnets 72 and 73. Operation of these motor magnets and interruption of the circuits thereof by the interrupter contacts cause operation of each of the switches B and B to the normal position where the motor magnets are short circuited through an obvious circuit extending from the normal contact of the bank 1!. of the respective switch to the lower stationary contact of the corresponding relay p or 2). Thus the switches B and B are now restored to their normal condition.

A circuit is now completed at the dispatchers station which extends from the neutral point on the battery 10 through the wiper and last contact of the bank t of switch A, wiper and normal contact of the bank t of the switch B, through third contact and wiper of the bank t5 of the switch T, motor magnet 71 and its interrupter contacts to the positive side of the battery 10. A circuit through corresponding elements at the remote station will likewise be completed. The motor magnets 71 and '71 are now energized operating the interrupter contacts and actuating switches T and T on to their fourth contacts. In this position a circuit is completed at the dispatchers station which extends from the negative side of the battery 10 through wiper and fourth contact of the bank t3 of the switch T, last contact and wiper of the bank 1: of the Switch A, motor magnet 48 and its interrupter contacts, 4th contact and wiper oi the bank t-4 of the switch T through the armature of relay P to the positive side 01' the battery 10. A circuit through corresponding elements at the remote station will likewise be completed. Motor magnets 48 and 49 will now be energized and in operating their interrupter contacts will cause the switches A and A to be returned to their normal position.

A circuit is now completed at the dispatchers station extending from the neutral point on the battery 10 through the wiper and normal contact of the bank t of the switch A, fourth contact and' wiper of the bank t-5 oi. the switch T, motor magnet '71 and its interrupter contacts to the positive side or the battery. A circuit through corresponding elements will be completed at the remote station thereby energizing the motor magnets 71 and 71' and causing the switches T and T to be operated on to their fifth contacts. When this occurs the switches A and A are again connected in circuit relation with the line conductors in the same way in which they were previously connected when the switches T and '1" were on their normal contacts. Since the circuit of the polarized relays p and p is now interrupted at the contacts of relays 36 and 44, the apparatus will now remain in its normal condition. Each successive four contacts on switches T and T are connected symmetrically. Thus the fifth and each successive fourth contact of these switches constitute a normal contact on which the switches rest between operations. In each position of the switches a circuit is completed extending from the interlock 35' through a corresponding contact in the bank 2' of switch A, wiper of the bank t-2 of switch A, conductor Ll, inner left-hand contacts of the relay 74, wiper of the bank t2 of the switch T, wiper of the bank i of the switch A, and winding of the corresponding indicating relay 26. A similar circuit will simultaneously be completed from the interlock 35' of a different apparatus unit through the bank 12 of the switch A, wiper of the bank t of the switch T, line conductor L2, outer righthand contacts of the relay 74, wiper of the bank t of the switch T, wiper of the bank i of the switch A, to a similar indicating relay 26. The indicating relays control the lights on their respective panels as previously described, each operation causing the white light w to be lighted until such time as the operator operates the key 4 to a position corresponding to the position of the corresponding remote unit. The relays 30 corresponding to each of the apparatus units operated are restored by circuits extending through the associated banks t and t" of the switches A and B.

The relay arrangement associated with the selector switches is such that an alarm bell 8 isoperated whenever a short circuit between any of the line conductors or an open circuit in any of the line conductors occurs. The manner in which this result is accomplished will now be explained. The circuit of the line conductor Ll extends from the positive side of the battery 13 at the remote station through relay 61', contacts of relay 65, normal contact and wiper of the bank 1', normal contact and wiper of the bank t-2 of the switch T, conductor L-1, inner left-hand contacts of relay 74, wiper and normal contact of the bank t--2 of the switch T, wiper and normal contact of the bank 1." of switch A, winding of relay'fil, contacts of relays "l5 and '76 to the intermediate point on the battery 10. Thus it will be seen that relays 61 and 61' are normally energized in this circuit provided relays 65 and '75 are energized, and the relays '16 and 74 are deenergized. The relay 61 at the dispatchers station is the master relay of the alarm circuit. The manner in which it causes operation of the alarm bell 8 will later be indicated.

The circuit of line conductor L2 extends from the intermediate point on the battery 13 through relay 44 at the remote station, normal contact and wiper of the bank 2'" oi. the switch A, normal contact and wiper oi the bank t of the switch T, line conductor L2, outer right-hand contacts of relay '14, wiper and normal contact of the bank t of switch T, wiper and normal contact of the bank 2" of switch A, relays 75 and 76 in parallel to the negative side of the battery 10. v The windings of relays 75, 76 are of about equal resistance, which may be in the neighborhood of 12,000 ohms, but the relay 76 has a resistance 77 connected in series therewith such that this relay does not carry suflicient current to hold its armature in the attracted position, whereas the relay 75 maintains its armature attracted. Relay 44 in the remote station which has a resistance of about 5000 ohms does not receive suflicient current to attract its armature in this circuit.

The circuit over line L3 extends from the positive side of the battery 13 through relay 65, normal contact and wiper of the bank s of switch A, normal contact and wiper of the bank t--6 of switch T, relay p, line L3, relay p, wiper and normal contact of bank t6 of the switch T, wiper and normal contact of the bank s of switch A, outer left-hand contacts of relay 74 to the negative side of the battery. Relay 65 receives suflicient current from this circuit to attract its armature, although the current flowing in this circuit is not sufliciently great to cause operation of relays p and p.

The line conductor L4 connects the inter- Q mediate points on the batteries 10 and 13 through the contacts of relay 50. As has previously been stated the relay 61 is a key relay of the alarm circuit in the dispatchers station and is connected I in series with the relay 61' at the substation which under certain conditions, which will be explained, operates simultaneously therewith, and which may be used for alarm purposes in the substation.

If an open circuit occurs in either line conduc- I.

tor Ll or L--4, the circuit of relays 61 and 61' will be interrupted and the relays will be deenergized. It will of course be apparent that interruptions of line L-4 by relay 50 in response to variations in potential in battery 13 will likewise f cause the alarm to be sounded. If an open circuit occurs in the line L2 relay 75 will be deenergized and in turn will deenergize relays 61 and 61. If an open circuit occurs in line L3 relay 65 in the substation will be deenergized and in turn will deenergize relays 61 and 61'.

If a short circuit occurs between lines Ll and L2, an additional circuit will be completed including the winding of relay 76 which will extend from the negative side of the battery 10 in the I..'='

pleted which extends from the negative side of battery 10 through the outer left-hand contactors of relay 74, wiper of the bank sof switch A in its normal position, wiper of the bank t-6 of switch T, winding of relay P. short circuit between lines L3 and L-1, wiper of t-2 of switch T, wiper of the bank i of switch A, contacts of relay 65 and low resistance relay 61 at the remote station to the positive side of the battery 13. This circuit causes operation of relay p, which in turn. causes the selector A to operate off from its normal contact thereby deenergizing the circuit of relays 61 and 61.

A short-circuit between line Ll and L4 places a direct short circuit across relay 61 causing this relay to be deenergized. The dispatcher may then manually operate relay 61 by pressing key 5 and energizing relay 74. This relay opens the circuit of relay 65 which in turn deenergizes relay 61'.

A short circuit between line L-2 and L3 causes relay p in the dispatchers station to become a low resistance shunt across high resistance relay which in turn reduces the potential across relay 75 to a value suflicient to cause relay 75 to become deenergized and in turn to deenergize relays 61 and 61. A short circuit between line L2 and line I.-4 will place neutral potential directly upon line L-2 thereby causing high resistance relays 76 to be immediately energized thereby to deenergize relays 61 and 61.

A short circuit between lines L3 and L-4 places neutral directly upon the synchronizing line thereby causing relay p to become energized and to operate the selector T continuously until stopped by the operator or until the short has been removed. This in turn deenergizes relays 61 and 61 and sounds the alarm.

It may occur that relay p will also be energized under this condition and operate selector A. The first off-normal contact of bank 2'" of switch A is normally disconnected from any source of potential and accordingly when switch A engages this contact relay 75 is deenergized. This likewise deenergizes relays 61 and 61'.

Thus it will be apparent that an open circuit in any of the line conductors or a short circuit between any of the line conductors will cause the alarm to be sounded.

When relay 61 becomes deenergized, by means of its left-hand contacts it interrupts the circuit of lamp G, thereby informing the operator that the apparatus is not in-the normal at rest condition. By means of its right-hand contacts it interrupts an obvious circuit for relay 89. Relay 89 by means of its inner left-hand contacts interrupts an obvious circuit for relay 79. Relay 79 is of the slug type and is slow to deenergize. Since relay 89 is a quick acting relay a circuit is momentarily completed which extends from the positive side of the battery 10 through the middle contacts of the start key 6, left-hand contacts of relay 79, inner right-hand contacts of relay 89, winding of relay 70 and right-hand contacts of relay 64 to the intermediate point on the battery. Relay 70 then becomes ener gized and completes an obvious buzzer circuit for the alarm bell 8, and at the same time through its inner contacts completes a holding circuit for itself. The operator,, however, may interrupt the holding circuit by operating the key 80 to its closed circuit position thereby energizing relay 64 and deenergizing relay 70. This in turn interrupts the operation of the bell 8.

When relay 89 becomes deenergized, it also by means of its outer left-hand contacts interrupts the starting circuit which extends from the negative side of the battery through the outer left-hand contacts of relay 89, upper contacts of start key 6 and thence through wipers of the banks i and t of the switches A and T through the line L--2 to the remote station. Thus upon occurrence of aline fault the start circuit is automatically interrupted and rendered inoperative. At the same time relay 89 momentarily completes a circuit which extends from the positive side of the battery 10 through the lower contacts of the start key 6, right-hand contacts of relays 89 and 79, both of which are closed simultaneously for an instant, winding of pilot light relay 83 and contacts of pilot light key 81 to the neutral point on the battery 10. Relay 83 is then energized and by means of its right-hand contacts completes a holding circuit for itself. By means of its left-hand contacts it operates the signal lamp 82 which remains lighted until the operator presses the key 81 thereby deenergizing relay 83.

Relay 74 in the dispatchers station is the emergency reset relay of the system. When the emergency reset key 5 is operated to its circuit closing position relay 74 becomes energized, and by means of its outer right-hand contacts and inner left-hand contacts immediately interrupts the circuits of the conductors Li and L--2 thereby preventing erroneous indications to be produced while the equipment is operating in response to the emergency reset key. At the same time by means of its outer left-hand contacts it interrupts the starting circuit which was previously traced. By means of its inner right-hand contacts it places neutral potential upon the conductor L3 between the relays p and p. Thus, if for any reason the selectors have stopped upon an erroneous off-normal contact the operator may, by pressing the emergency reset key 5, operate the selectors in the dispatchers station and also those at the remote station independently of each other from the position they occupy which may be corresponding or non-corresponding positions to their normal contacts.

It will now be apparent that if the equipment is operated from its normal contact due to an automatic operation of a remote apparatus unit, or, for any other reason, other than the operation of the start key 6 the alarm bell will be sounded. If the equipment is started however by operating the start key, the circuit of the relays 70 and 83 will be interrupted at the contacts of the start key and, accordingly, cannot be completed upon operation of relay 89. The hell 8 and signal lamp 82, therefore, remain deenergized.

The relay 61' in the remote station may, as has been stated, be employed to operate a signal device in a manner equivalent to operation of the bell 8, or it may be used for the purpose of operating counting or other indicating or control mechanism as desired in the remote station.

While I have shown particular embodiments of my invention, it will of course be understood that I do not wish to be limited'thereto since many modifications, both in the circuit arrangements and instrumentalities employed, may be made, and I therefore contemplate by the appended claims to cover all such modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In a remote control system, a plurality of stations, a normally unoperated selector mechanism in each station, conductors extending between said stations, means for operating said selector mechanism in the different stations in synchronism over certain of said line conductors, means including said selector mechanisms for performing remote operations over at least one other of said conductors, a source of current, a relay having a winding, means including said mechanisms for connecting said relay winding in series with said source and said other conductor only when said mechanisms are in their normal positions, means responsive to a short-circuit between the conductors over which said mechanisrns are operated in synchronism for eifecting the movement of one of said mechanisms out of its normal position whereby said relay winding is deenergized, and signal means responsive to the deenergization of said relay winding.

2. In a remote control system, a dispatchers station, a remote station, a selector in each station, means including a circuit extending between the stations for operating said selectors in synchronism, said circuit being insufficiently energized in the normal condition to operate said selectors, a control circuit extending between the stations, a relay normally connected in said synchronizing circuit at the remote station and arranged upon interruption thereof to interrupt said control circuit, alarm means in the dispatchers station responsive to the condition of the control circuit, and means for shunting said relay thereby sufficiently to increase the energization of said circuit to cause operation of the selectors.

3. In a remote control system, a first station, a second station, normally unoperated selectors in each station, means including a conductor extending between the stations for synchronously operating said selectors through different positions, means including another line conductor for performing control operations in one station from the other station through said selectors in different positions thereof, a source of potential in said other station, connections whereby said synchronizing and control means are energized therefrom, means responsive to the condition of said source for interrupting the circuits through said synchronizing and control means when said source becomes inoperative.

4. In combination, a first station, a second station, a selector in each station having a normal position and a plurality of other positions, means including a pair of line conductors for synchronously operating said'selectors from the normal position through said other positions, a plurality of conductors extending between said selectors, signal means connected in circuit with one of said conductors, and the selectors when the selectors are in their normal positions, and operable in response to an interruption in said circuit, and means responsive to a short circuit between different of said conductors to operate at least one of said selectors from the normal position thereby to cause operation of said signal device.

5. In combination, a station, a second station, a plurality of apparatus units in said second station, selector means in each station, each of said selector means having a normal position and a plurality of other positions, means operable over certain of said conductors to operate said selector means through each of said positions, a control relay for each of said apparatus units, means operable through said selector means in different positions thereof to control said control relays, automatic means dependent upon the position of one of said control relays for controlling one of said apparatus units, time delay means responsive to a fault in said line conductors and to movement of one of said switches from the normal position for operating said one control relay to a position such that the corresponding apparatus unit is controlled by said automatic means, the time delay of said last means being sufiicient to permit normal control of said relays through said selector means without operating said associated relay to said position.

6. In combination, a station, a second station, a plurality of apparatus units in said second station, selector means in each station having a normal position and a plurality of other positions, means responsive to operation of any of said apparatus units to operate said selector means synchronously from the normal position through each of said other positions, a circuit for each apparatus unit, each circuit including contacts on the corresponding apparatus unit and the selector means in the corresponding position, means controlled by said circuit to interrupt operation of said selector means in the normal position, and means controlled from the first station and operable after failure of said last means to interrupt operation of said selectors in the normal position to synchronize said selectors in said normal position.

'7. In combination, a station, a second station, a plurality of apparatus units in said second station, selector means in each station having a normal position and a plurality of other positions, means responsive to operation of any of said apparatus units to operate said selector means synchronously from the normal position through each of said other positions, a circuit for each apparatus unit, each circuit including contacts on the corresponding apparatus unit and the selector means in the corresponding position, means controlled by said circuit to interrupt operation of said selector means in the normal position, means operable after failure of said last means to interrupt operation of said selectors in the normal position to synchronize said selectors in said normal position, and means in the dispatchers station whereby the apparatus unit, the operation of which resulted in said failure, maybe determined.

CLYDE E. STEWART. 

